#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
#include<stdbool.h>

struct TreeNode {
    int val;
    struct TreeNode *left;
    struct TreeNode *right;
};


bool isMirrorTree(struct TreeNode* p, struct TreeNode* q)
{
    if (p == NULL && q == NULL)
        return true;
    if (p == NULL || q == NULL)
        return false;
    if (p->val != q->val)
        return false;

    return isMirrorTree(p->left, q->right) && isMirrorTree(p->right, q->left);
}

bool isSymmetric(struct TreeNode* root)
{
    if (root == NULL)
        return true;
    return isMirrorTree(root->left, root->right);
}